Australia 4 for 297 (Watson 161*) beat England 294 (Pietersen 78, Strauss 63) by six wickets
Shane Watson produced one of Australia's finest one-day hundreds to carry them to a record-breaking six-wicket win at the MCG with the highest successful chase on the ground. His unbeaten, career-best 161, Australia's fifth highest individual effort, allowed them to hunt down 295 with five balls to spare and take an early lead in the seven-match series.
After a summer that has become synonymous with Watson's fifties this was a huge moment for the allrounder and both his hundred, and later the 150, were celebrated with arms aloft in front of an appreciative 34,000 fans. He kept his cool when the asking rate began to climb and fittingly was the man to finish it with a six over long-off.
On a surface where scoring became hard work against spin and a soft ball this was a mammoth pursuit and for most of the time Australia had it under control. However, there was just a moment when England were giving themselves a chance, partly helped by a painful innings from Michael Clarke who eventually drove to mid-off.
Steve Smith was then strangely promoted to No.4, clearly to take advantage of the Powerplay, above the likes of Cameron White and the Hussey brothers. He swung wildly before being caught at short third-man and although Australia had plenty of wickets left it gave England a timely boost. However, Mike Hussey provided the late spark with 21 off 15 balls and Cameron White, in front of his home supporters, had the muscle to ease the pressure.
This, though, was Watson's match. He was quickly out of the blocks with a second-ball clip to fine leg and collected boundaries in each of the first five overs against Tim Bresnan and Chris Tremlett. He and Brad Haddin knew how important it was to make the most of the hard ball before the spinners could start have a say on proceedings.
Tremlett nearly provided the breakthrough when Watson top-edged a pull but Jonathan Trott couldn't back-pedal far enough at mid-on. Andrew Strauss opted to hold back his bowling Powerplay to try and reign in the scoring with his slow bowlers, but after three overs called the restrictions which signalled another charge from the openers.
Bresnan's comeback over went for nine and Shahzad's opening two deliveries were dispatched by Haddin who was starting to catch up with his partner. The breakthrough went to Graeme Swann as Haddin tried to clear the large leg-side boundary. Watson, though, continued towards his hundred with the occasional four to keep the required rate under control. When he reached three figures he had nearly two thirds of Australia's runs.
However, problems were starting to develop at the other end. Clarke, filling Ricky Ponting's shoes at No.3, continued to be horribly out of form and his 57-ball 36 put increasing pressure on Watson. Clarke was even booed by home supporters when he played out dots and cheered when he got off strike. For his sake it was a good job Watson got them over the line.
England will see this as a major missed opportunity because Australia were poor in the field, but they kept giving away wickets after an opening stand of 90 in 12 overs between Strauss and Steve Davies. The next best partnership was 50 for the sixth wicket between Kevin Pietersen, who top-scored with 78, and Michael Yardy, but Pietersen fell early in the batting Powerplay which hampered England's chances of a late charge.
This was Pietersen's first fifty-plus score in one-dayers since he made an unbeaten 111 at Cuttack in November 2008, although due to injury and being dropped he has only had 17 innings in that period. Still, having been brought back at the expense of Paul Collingwood, who paid for his poor Ashes form, he needed to justify that faith and it went to plan until Mitchell Johnson's superb soccer skills found him well short.
Pietersen and Ian Bell were starting to form a useful stand when Smith chipped in with two important wickets. It was a good day for Australia's part-time spinners because David Hussey also bagged a brace. Smith had Bell and Eoin Morgan caught in the covers to leave England 5 for 186 and needing a rebuilding job.
However, Haddin had a shocking day behind the timber and the third of his misses reprieved Pietersen on 37 moments after the loss of Morgan. Instead, Pietersen responded with consecutive straight sixes off Hussey to move to his fifty and later added a third when he drilled Xavier Doherty into the sightscreen.
Davies had been the earlier major beneficiary of Australia's generosity in the field when he was given four lives; a missed run out, being caught off a no-ball against Brett Lee, Haddin's first missed stumping and a sharp catch to cover. There was also some wayward bowling to feast on from Johnson and Doug Bollinger before Davies missed a big sweep at Hussey, who then claimed Trott.
Strauss had also been given a life on 48, another error from Haddin, and looked set to make Australia pay until the lack of pace off the surface led to him spooning Lee to midwicket. In the end the lack of a batsman converting to three figures hurt England. Watson showed what a difference it can make.
Andrew McGlashan is an assistant editor at ESPNcricinfo